from django.db import models
from django.utils import timezone
import datetime

from django.contrib import admin


class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField("date published")
    """
    但你在调用对象的str()时候，就会调用__str__()方法。
    """
    def __str__(self):
        return self.question_text
    @admin.display(
        boolean=True,
        ordering="pub_date",
        description="Published recently?",
    )
    def was_published_recently(self):
        now = timezone.now()
        return now - datetime.timedelta(days=1) <= self.pub_date <= now


class Choice(models.Model):
    question = models.ForeignKey(Question, on_delete=models.CASCADE)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)

    def __str__(self):
        return self.choice_text


class book(models.Model):
    title = models.CharField(max_length=200)
    author = models.CharField(max_length=200)
